A plasticity model for simulation of industrial powder compaction processes

Oliver, J.; Oller, Sergio; Cante, Juan

doi:10.1016/0020-7683(95)00249-9

Cited by 53 publications

(98 citation statements)

References 13 publications

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“…We assume an elliptic yield function of the form proposed by Doraivelu et al (1984) and Oliver et al (1996),…”

Section: Plastic Responsementioning

confidence: 99%

“…The purpose of this work is to extend this procedure to more realistic plastically deforming granules. To this end, we first describe an appropriate constitutive model for the granule behaviour, based on the elliptic yield surface proposed by Doraivelu et al (1984) and Oliver et al (1996), which allows porous particles to both deform and to densify plastically, whereas only volume-preserving plastic deformation is possible for nonporous ones. The reason for introducing this rather elaborate model is that porous granules often are encountered in pharmaceutical applications.…”

Section: Introductionmentioning

confidence: 99%

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Compression mechanics of granule beds: A combined finite/discrete element study

Frenning

2010

Chemical Engineering Science

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Compression of three-dimensional beds comprising of 1000 plastically deforming initially spherical granules is investigated by using the combined finite/discrete element (FE/DE) method. The material model is formulated within the framework of multiplicative plasticity, and utilizes a density-dependent elliptic yield surface that allows porous particles to both deform and to densify plastically, whereas only volume-preserving plastic deformation is possible for nonporous ones. Granules with different characteristics (yield stress and initial porosity) are studied, and the relationship between the single-granule properties and the global compression behaviour of the granule bed is investigated. It is demonstrated that the FE/DE method may shed light on the deformation and densification behaviour of individual granules, since the size and shape of each granule are continually determined as an integral part of the solution procedure, and that the method thus provides a comprehensive picture of the processes occurring during confined compression of granular materials.

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“…We assume an elliptic yield function of the form proposed by Doraivelu et al (1984) and Oliver et al (1996),…”

Section: Plastic Responsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Compression mechanics of granule beds: A combined finite/discrete element study

Frenning

2010

Chemical Engineering Science

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“…This procedure is known as the "flow approach", and was first presented in the work of Goon et al [42]; Zienkiewicz and Godbole [43] gave a more general solution for viscoplastic materials. The powder filling is simulated by adopting constitutive relations developed for compaction processes [6,12,44], in the frame of soil constitutive models, but with a complete reinterpretation of the parameters. All the governing equations will be described next.…”

Section: Constitutive Model For the Powdermentioning

confidence: 99%

“…The angled bracket in (5) represents the Macaulay bracket that takes the value of the argument when positive and is zero otherwise. This term ensures no plastic flow when stresses are below yield (6) Clearly as the constant 0   , equation (6) gives the behavior of an ideally plastic material. Here, the proposed yield condition is a double-surface plasticity model, based on a combination of a convex yield surface consisting of a frictional envelope, such us a Drucker Prager yield surface and an elliptical cap surface which closes the open space between the frictional surface and the hydrostatic axis ( figure 12).…”

Section: Strain Rate Relationmentioning

confidence: 99%

“…During the last twenty years, several research groups have developed different numerical models to capture the evolution of the most relevant properties such as density and applied forces, during the compaction process. Most of them [2][3][4][5][6][7][8][9] have concentrated their efforts on the numerical simulation of the compaction itself and some [10][11][12] have included the transfer stage. However, die filling has been little analysed.…”

Section: Introductionmentioning

confidence: 99%

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Flow regime analyses during the filling stage in powder metallurgy processes: experimental study and numerical modelling

et al. 2010

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Experimental and numerical studies of powder\ud flow during the die filling stage in powder metallurgy cold\ud compaction processes are presented. An experimental setting\ud consisting of a horizontal pneumatically activated shoe,\ud a vertical die and high-speed video system has been designed.\ud The experiments show the existence of three flow regimes:\ud continuous, transitory and discrete, which are identified in\ud terms of the particle size, the morphology and the speed of\ud the shoe. In the continuous regime the powder flows in a progressive\ud manner but in the discrete one some perturbations\ud appear as a consequence of a shear band formation that forms\ud discrete avalanches. A numerical model, based on a ratedependent\ud constitutive model, via a flow formulation, and in\ud the framework of the particle finite element method (PFEM)\ud is also proposed. For the purpose of this study, the use of the\ud PFEM assumes that the powder can be modelled as a continuous\ud medium. The model, provided with the corresponding\ud characterisation of the parameters, is able to capture the two\ud fundamental phenomena observed during the filling process:\ud (1) the irreversibility of most of the deformation experienced\ud by the material and (2) the quick dissipation of the potential\ud gravitatory energy of the granular system through the inter-particle friction processes, modelled by the plastic dissipation\ud associated with the material model. Experimental and\ud numerical results have been compared in order to study the\ud viability of the proposed model.Peer ReviewedPreprin

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Adaptive finite element remeshing in a large deformation analysis of metal powder forming

Khoei

Lewis

1999

Numerical Meth Engineering

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In this paper, a general framework for the ÿnite element simulation of powder forming processes is presented. A large displacement formulation, based on a total and updated Lagrangian formulation and an adaptive ÿnite element strategy based on error estimates and automatic remeshing techniques are utilized. To describe the constitutive model of the highly non-linear behaviour of powder materials, an elliptical cap model based on a hardening rule to deÿne the dependence of the yield surface on the degree of plastic straining is applied. The interfacial behaviour between the die and powder is modelled by using a plasticity theory of friction in the context of an interface element formulation. Finally, the powder behaviour during the compaction of a set of complex shapes are analysed numerically. The simulation of the deformation is shown as well as the distribution of relative density contours at di erent time stages. The results clearly indicate that the algorithm makes it possible to simulate the powder forming problems e ciently and automatically.

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A plasticity model for simulation of industrial powder compaction processes

Cited by 53 publications

References 13 publications

Compression mechanics of granule beds: A combined finite/discrete element study

Compression mechanics of granule beds: A combined finite/discrete element study

Flow regime analyses during the filling stage in powder metallurgy processes: experimental study and numerical modelling

Adaptive finite element remeshing in a large deformation analysis of metal powder forming

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